Cards won’t be counted

Hi, a few months ago I came across a bug and now I’m having it again.
In a nutshell, the app doesn’t count number of cards correctly. It goes up to around 10 and then starts over. This has happened before on my older phone (iPhone 5c) and persists now (iPhone SE). I am using the latest version.
P. S. When I first installed Lingvist on this new phone, which was around two weeks ago, there were no bugs, but from today it happens again. Restarting won’t help.

Unfortunately, I can't help you with this problem, but maybe I can add additional information for the developers. I've seen something similar when I learned across the "midnight reset" - meaning when I started a learning session shortly before midnight and kept going into the next day. Maybe this is what happens to you as well? So far, the problem has rectified itself after some time, maybe when the next batch of cards where due (but this is mostly a guess).